The neuropharmacology of major anticonvulsant drugs (phenytoin, phenobarbital, dipropylacetate, diazepam, and bromide) will be studied by extracellular and intracellular recording techniques in the isolated sympathetic ganglion of the bullfrog. Dose-effect analyses for several parameters of synaptic function and for membrane electrical properties will be performed to determine primary site of action on the neural components of the synapse. Such studies will be performed on ganglia isolated from normal frogs and also on those isolated from frogs treated chronically with the anticonvulsant drug to be investigated neuropharmacologically. For the latter work elimination kinetics and metabolism of each anticonvulsant in the bullfrog will have to be determined to establish dose regimens necessary to achieve desired steady state drug levels.